RU104728U1 - DEVICE FOR ACOUSTIC AND EMISSION DIAGNOSTICS OF PORCELAIN INSULATORS - Google Patents

Abstract

 An acoustic emission diagnostic device for porcelain insulators, comprising a decision unit, an information display unit, and at least one time discriminator and one pair of measuring channels designed to connect to different points on the surface of the diagnosed insulator, each measuring channel of the pair contains an acoustic transducer connected in series , a filtering unit, an envelope detector, and a threshold element in at least one channel of the pair, an account is connected to the output of the threshold element a pulse counter with a register, the output of which through a series-connected start block and timer is connected to the clock inputs of the pulse counter and register, while the input of the decision block is connected to the register output, the inputs of the temporary discriminator are connected to the outputs of the threshold elements of the measuring channels of the pair, and the inputs of the display block information to the output of the decision-making unit and the output of the temporary discriminator.

Description

Technical field

The invention relates to a test technique and can be used for acoustic emission (AE) diagnostics of high-voltage porcelain insulators.

State of the art

It is known that the device for acoustic emission monitoring of porcelain insulators, selected as a prototype, contains an information display unit, at least two measuring channels, each of which includes an acoustic transducer, a filtering unit, an envelope detector, a threshold element, a pulse counter, and a register the output of which is connected through a series-triggered start block and timer to the clock inputs of the pulse counter and register, and a decision block, the inputs of which are connected to an output measuring channels, and to the output - input display unit [Russian utility model patent RU 58221 of category IPC G01N 29/14 by 2006].

A disadvantage of the known device is the lack of localization of the defect in the body of the diagnosed insulator, which reduces the information content and reliability of the diagnosis.

Utility Model Essence

The technical result of the utility model is the localization of the detected defect in the body of the diagnosed insulator.

The subject of a utility model is a device for acoustic emission diagnostics of porcelain insulators, comprising a decision unit, an information display unit and at least one time discriminator and one pair of measuring channels designed to connect to different points on the surface of the diagnosed insulator, each measuring channel of the pair contains a series-connected acoustic transducer, a filtering unit, an envelope detector and a threshold element in at least one channel of the pair to the output at the threshold element, a pulse counter with a register is connected, the output of which through a series-connected start block and a timer is connected to the clock inputs of the pulse counter and register, while the input of the decision block is connected to the register output, the inputs of the temporary discriminator are connected to the outputs of the threshold elements of the measuring channels of the pair, and the inputs of the information display unit to the output of the decision unit and the output of the temporary discriminator.

The above set of features of a utility model provides the specified technical result.

Utility Model Implementation

The block diagram of the device in the minimum configuration is shown in figure 1., which shows the decision block 1, the information display block 2, the time discriminator 3 and a pair of measuring channels 4 and 5, designed to connect with different points on the surface of the diagnosed insulator.

Each measuring channel 4 and 5 contains sequentially connected acoustic transducer 6, filtering unit 7, envelope detector 8, threshold element 9. In channel 4, a pulse counter 10 with register 11 is connected to the output of threshold element 9.

The output of the register 11 through the sequentially connected start block 12 and the timer 13 is connected to the clock inputs of the pulse counter 10 and the register 11. The output of the register 11 is also connected to the input of the decision block 1.

The inputs of the discriminator 3 are connected to the outputs of the threshold elements 9 of the measuring channels 4 and 5, and the inputs of the information display unit 2 to the output of the decision unit 1 and the output of the temporary discriminator 3.

The information display unit 2 is equipped with the NORM and DEFECT indicators, as well as an indicator of the distance of the detected defect, for example, from the installation site of the acoustic transducer 6 on the diagnosed insulator of one (any) of channels 4 or 5.

The device operates as follows.

Converters 6 channels 4 and 5, forming a pair, are installed on one diagnosed insulator at different points on its surface. For example, the transducer 6 of the channel 4 is installed near the lower flange, and the transducer 6 of the channel 5 is installed near the upper flange of the support insulator.

Then the test mechanical loading of the insulator by the bending moment of force is carried out (using a separate hydraulic loading device). The magnitude of the force is selected based on the normalized non-destructive value for this type of insulator.

Latent defects of insulators (developing cracks) are detected as a result of the analysis of changes in the acoustic emission activity of insulators that occurs upon double mechanical loading.

After applying a load to the diagnosed insulator, each transducer 6, consisting of a sensitive piezoelectric transducer with an amplifier, perceives acoustic vibrations that occur in the insulator during mechanical loading, and converts them into an electrical signal.

In each channel 4 and 5, the signal from the converter 6 through the connecting cables enters the block 7, which is a frequency-selective amplifier that removes high-frequency interference, and then passes through the detector 8. The detector 8 emits an envelope of the amplified high-frequency signal, which is fed to the threshold element 9 , designed to isolate pulses with the suppression of noise and interference. In channel 4, the AE pulse sequence generated at the output of element 6 is counted by counter 10. The counting result is stored in register 11 and can be displayed. When the counting result stored in the register 10 goes beyond certain limits, block 12 starts a timer 13, which resets the counter 10 and register 11 for counting pulses in the next measurement cycle. The results of counting pulses coming from register 11 are logically processed (with the discarding of results that go beyond the statistically established limits of reliability) to block 1 and then converted by block 2 into codes that control the indicators "NORM" and "DEFECT".

In the absence of a defect in the insulator, acoustic emission pulses do not occur, and there will be no electrical signals at the output of the transducers 6.

In the presence of a defect in the insulator, electrical signals corresponding to acoustic emission pulses in the insulator body appear at the outputs of the transducers 6 of both channels of the pair.

The pulses from the outputs of the threshold elements 9 of both channels 4 and 5 of the pair also arrive at the first and second inputs of the temporary discriminator 3.

Due to the spatial diversity of the installation places of the transducers 6 on the diagnosed insulator and the finite time of the passage of pulses from the place of their occurrence inside the insulator to the installation location of the transducers 6, these pulses will be fixed by the discriminator 3 with some time shift.

At the same time, a signal is generated at the output of discriminator 3, the duration of which is determined by the difference in time of arrival of the acoustic pulse from the threshold elements 9 of channels 4 and 5, which is equal to the difference in the time of passage of the acoustic emission pulse from the defect in which the pulse occurs to the installation sites of the 6 channel transducers couples.

According to the known distance between the transducers, the typical propagation speed of the acoustic signal in china and the parameter (for example, duration) of the output signal of the discriminator 3, the display unit 2 displays the distance from the installation location on the diagnosed insulator, for example, the transducer 6 on the lower flange of the insulator, to the place the location of the defect in the body of the insulator,

Thus, the acoustic emission monitoring device makes it possible to determine not only the absence or presence of a defect, but also its location, which increases the reliability and informativeness of the diagnostics of the state of the porcelain insulator and, thereby, improves the operational reliability of high-voltage equipment.

Claims (1)

An acoustic emission diagnostic device for porcelain insulators, comprising a decision unit, an information display unit, and at least one temporary discriminator and one pair of measuring channels designed to connect to different points on the surface of the diagnosed insulator, each measuring channel of the pair contains an acoustic transducer connected in series , a filtering unit, an envelope detector, and a threshold element, in at least one channel of the pair, an account is connected to the output of the threshold element a pulse counter with a register, the output of which through a series-connected start block and timer is connected to the clock inputs of the pulse counter and register, while the input of the decision block is connected to the register output, the inputs of the temporary discriminator are connected to the outputs of the threshold elements of the measuring channels of the pair, and the inputs of the display block information to the output of the decision-making unit and the output of the temporary discriminator.